This invention relates to lens caps for optical instruments; and more particularly relates to a novel and improved protective lens cap for shielding the user's eyes from incident light from any angle thereby enhancing the viewing quality of the optical instrument.
It is well known to provide a protective lens cap for an optical instrument to prevent the lens from being scratched or otherwise damaged. For example, U.S. Pat. No. 98,185, issued to Reynolds, discloses the design for a binocular telescope with hinged dust covers; U.S. Pat. No. 3,829,194, issued to Van Exel, discloses a binocular having a removable cover plate for protection ofthe objective and eyepiece lenses; U.S. Pat. No. 4,641,932, issued to Harms, discloses a slidable protective lens cap which is permanently attached for an optical device; U.S. Pat. No. 5,155,624, issued to Flagler, discloses a disposable protective lens cap having an optically clear portion for protection of the objective lens of a microscope which is used during surgery.
However, there has been little in regard to protective caps for lenses which have the additional feature of blocking incident light from the user's field of vision. Incident light may drastically reduce the image quality of objects viewed through an optical instrument, such as, a binocular, telescope, or microscope. In fact, a high amount of incident light may completely obstruct the image viewed through an optical instrument. Usually, a user will use his or her hands in an attempt to block this incident light and improve the image quality. However, it may be difficult for the user to block the incident light while maintaining a firm grip on the optical instrument. U.S. Pat. No. 3,020,802, issued to Rantsch, discloses the use of ocular rubber sleeves in combination with a cover such that the cover forms a certain protection against the lateral entrance of light when it is removed from the ocular lens. However, often the source of incident light penetrates the field of vision from angles other than the outside-lateral angle of the user, such as, from above the user or various other angles. This problem is especially critical for users in the field who encounter a vast number of different lighting situations.
It is therefore desirable to provide a lens cap apparatus that is capable of shielding the user's eyes from incident light from all angles; and when used in pairs on binoculars, are adjustable to fit varying widths and shapes of different people's heads, and can be used in conjunction with eye glasses.